Allward



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TEN-KEY CALCULATING MACHINES Filed May 1, 1958 5 Sheets-Sheet 4 1961 w. ALLWARD TEN-KEY CALCULATING MACHINES 5 Sheets-Sheet 5 Filed May 1, 1958 INVENTOR.

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United States Patent M 3,009,634 TEN-KEY CALCULATING MACHINES Walter Allward, Evanston, Ill., assignor to Comptometer Corporation, Chicago, 111., a corporation of Illinois Filed May 1, 1958, Ser. No. 732,349 17 Claims. (Cl. 235-60) This invention relates in general to calculating machines, and more particularly to ten-key listing calculators.

A principal object of the invention is to provide such a machine with simplified and improved mechanism which enables optional performance of decimal calculations or those involving non-decimal amounts or items, such as employed in the British currency system.

Another object of the invention is to adapt a wellknown ten-key decimal machine for use with the British currency system with a minimum of alterations and additions. This object is attained by increasing by two the number of pins in each column in the pin carriage, adding a and an 11 pence key, substituting .a rack mechanism in the units order which comprises one rack movable two regular increments further than the usual racks and a second rack with reduction gears between those racks to move the second for the same number of increments as the first but with each increment shorter in length in the ratio of 10:12, using a printing wheel in the units order having the numerals 0 to 11 thereon and operable by that second rack, changing the carrying mechanism between the third and fourth denominational orders to efiect a transfer after each second tenth of a revolution of the accumulator and printing Wheels in the third order, and adding novel means for preventing any operation in the three lowest orders when the machine is to be used in decimal calculations.

Another object of the invention is to immediately block operation of the printing mechanism in the three lowest orders upon depressing a special control key to set the machine for decimal calculations and, with that key, to release a special zero stop to limit rack movements in the three lowest orders, and to condition or render operable a normally ineffective mechanism that will be operated in response to subsequent depression of any regular machine cycle control key to elfect actuation of a step-over mechanism for moving the pin carriage the distance subtended by three columns before release of the racks.

A further object is to eliminate the necessity of depressing the zero digit key three times when entering a whole number of pounds during use of the machine for British currency calculations. This object is accomplished by providing a three zero control key depression of which immediately effects actuation of the step-over mechanism and releases the special zero stop.

Another important object of the invention is to make operation of such three zero key as nearly similar as possible to that of the regular zero digit key.

A further object is to lighten the resistance against operation of such novel control keys and minimize the manual effort required to depress them or return the one that is latched down to normal raised position.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description which, when taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

In the drawings:

FIGURE 1 is a top plan view of a calculating machine embodying the features of my invention;

FIG. 2 is a view as seen from the right side of the machine with parts in elevation and partly in section;

3,009,634 Patented Nov. 21, 1961 FIG. 3 is a view similar to FIG. 2, as seen from the left side of the machine;

FIG. 4 is a perspective view of the forward part of the machine with the casing and keyboard section removed and looking downwardly thereon;

FIG. 5 is a detail plan view of the novel rack and pinion mechanism employed in the pence column;

FIG. 6 is a detail elevation of the mechanism of FIG. 5, with the pinion shaft in section;

FIG. 7 is a transverse elevational view of the keyboard section as seen from the rear thereof; and

FIG. 8 is a view similar to FIG. 7 looking at the keyboard section from the front of the machine.

As previously noted, the present invention is incorporated in a ten-key calculating machine to facilitate optional use thereof for decimal or whole number calculations, on the one hand, or non-decimal calculations, such as required in the use of the British currency system. Since the present invention contemplates use of wellknown ten-key mechanism and the additional of novel means thereto for enabling its optional use for decimal or non-decimal calculations, a better understanding may be had by first referring briefly to the old or well-known mechanisms.

These include the usual digit keys 11 (FIG. 1) which are employed to set into a control mechanism, comprising -a pin carriage 12 (FIGS. 2 and 4), the amounts desired to be entered into the accumulator mechanism 13 (FIG. 2) and listed by the printing mechanism 14 in response to operation of the actuating means, which includes the usual rack bars 15, the actuators or stop bars 16 pivotally connected to the latter, respectively, at 17, and the associated springs 18. The pin carriage 12 normally is retained in its home position of FIG. 4 by the usual escapement mechanism which includes the teeth 19 provided along the forward edge thereof. In that home position, the leftmost row of pins 21 in the pin carriage is disposed beneath the lower or active ends of the several digit keys 1.1, so that depression of a digit key would result in downward setting movement or depression of a pin 21 in that leftmost row corresponding in digital value to the key depressed. Depression of a digit key also moves downwardly the inner ends of a pair of escapement pawls 22,23 from their normal position of FIG. 8. The right-hand pawl 22. normally engages the teeth 19 of the pin carriage and is thereby moved downwardly out of engagement therewith, while the left-hand pawl 23 is being moved downwardly simultaneously into engagement with the teeth 19, in wellknown manner. Release of the depressed digit key results in these escapement pawls being spring returned to their normal position of FIG. 8 and completion of spring-actuated movement of the pin carriage 12 to the left in FIG. 4 the distance equal to that between denominational orders of the pins 21 to align the next order thereof with the active lower ends of the digit keys. As is well known, the pin carriage Z1 is slidably mounted on a pair of transverse rods 24 and is constrained for movement from right to left of the machine by a spring 25.

Following such selective depression of pins 21 in one or more of the denominational orders of the pin carriage,

depression of any one of the several well-known control 3 orders in which pins 21 have been depressed. Such movements of the bars 15, 16 are permitted as a result of rotation of the main cam shaft 27 to unblock the levers 28 which support at their upper ends the rack return bail 29 that normally blocks such operation of the actuating mechanism. Stops 31 on the bars 16 in the actuated orders contact the depressed pins 21 to determine the extent of such rack bar actuation. In those orders of higher denominational value in which an actuation is not to be effected, these stops 31 contact a depending flange on the lefthand portion of the pin carriage 12 which prevents such movement in well-known manner. The second half of a machine cycle includes cam return of the bail 2.9 to its normal position of FIG. 2 to return the actuated bars 15, 16. That phase of the machine cycle also normally includes counterclockwise movement of a lever 32 (FIG. 4), which is pivotally connected by a link 33 to the pin carriage 12, to return the latter to the right side of the machine. In this return movement of the pin carriage, it is moved to the right beyond its home position of FIG. 4 against a resilient buffer 64 to effect resetting of any pin 21 in the leftmost order thereof which may have been depressed, and rebounds to the left to its home position of FIG. 4 wherein it is latched by the escapement pawl 22. The mechanism for accomplishing these functions is illustrated and described in United States Letters Patent No. 2,823,854, issued February 18, 1958.

The old mechanism incorporated in the present machine also includes a column indicator extending upwardly from a bracket 35 (FIG. 4), that is attached to the pin carriage 12, which cooperates with a scale or indicia 36 to visually indicate which of the several denominational orders of pins 21 are aligned at any given time with the lower active ends of the digit keys 11. The column indicator bracket 35 also is provided with an upwardly ex tending finger piece 37 which may be moved selectively to the right, following the setting of any value in the pin carriage and before initiation of a motor-driven machine cycle, to return the pin carriage and reset to inactive position any of the pins 21 previously actuated.

In order to employ such a machine for non-decimal calculations, such as required in connection with British currency, the three lowest denominational orders of the actuating, accumulator, and printing mechanisms have been changed to adapt them to shillings and pence. Since twenty shillings make a pound, the second and third lowest orders required only a change of numeral and printing wheels in the third order having alternate blanks or zeros and ones and a change in the tens transfer or carry mechanism to effect 'a carry to the fourth lowest denominational order in response to each fifth of a revolution of the numeral wheel in the third lowest denominational order. In the lowest denominational order, means are provided to transpose each decimal incremental movement of the rack 15 therein into an effective movement of a second rack in the ratio therewith of 10:12, and the addition of numeral and printing wheels carrying equally spaced indicia from to 11.

In FIGS. and 6 are illustrated the means employed for so changing the effect of the incremental movements of the rack 15 in the lowest denominational order of the machine. This lowest denominational order rack 15 meshes with a relatively large gear 38 rotatably mounted on the printing pinion shaft 39, and a relatively small pinion 41 having the same number of teeth as the gear 38 is rigidly secured to the gear 38 in any suitable manner. This smaller pinion 41 meshes with an auxiliary rack 15a which actuates the lowest denominational order of the accumulator. A special printing wheel 14a carrying the numerals 0 through 11 is rotated by the gear 38.

It will be appreciated that a further requirement to enable use of this mechanism for calculations involving British currency is the addition of a ten and an eleven digit key 11a and 11b, respectively, for use in entering amounts of ten and eleven pence. These additional digit keys are mounted in the manner best illustrated in FIGS. 1 and 7 and, like the regular digit keys 11, have laterally extending active lower ends aligned longitudinally of the machine with the lower active ends of the other digit keys to effect depression of the corresponding pins 21 in any one of the denominational orders of such pins. The pin carriage 12 has been altered to provide eleven pins 21 in each denominational order rather than the nine required in a decimal machine.

Whenever a zero is included in an amount being entered in the machine, the zero digit key 11 is depressed by the operator to actuate the zero pin 21 in the proper denominational order. The zero pins 21 cooperate with the stops 31 of the bars 16 to permit rearward movement of the latter only suificient to effect subsequent printing of a zero during the subsequent machine cycle. This is true in both the decimal and non-decimal orders. When the machine is employed with problems involving British currency and it is desired to enter a whole number of pounds, the amount including no shillings or pence, unless otherwise provided it is necessary after the number of pounds have been entered by depressing the appropriate digit keys, to actuate the zero digit key 11 three times.

The present invention includes the provision of novel means for eliminating the necessity of the last two zero digit key depressions under such circumstances by pro viding an auxiliary control member or additional control key depression of which will have the same end effect as three successive depressions of the zero digit key 11 in entering a whole number of pounds. This three zero" control key is designated herein by reference numeral 42. The depression of this key 42 results in two related functions. It causes an immediate stepping to the left of the pin carriage 12 a distance equivalent to that subtended by three denominational orders of pins 21. It also renders operative normally inoperative means comprising novel mechanism for controlling subsequent rack movement in the three lowest denominational orders in the same manner as if the denominationally corre sponding zero pins 21 had been depressed. To effect the first-noted function, a second escapement or step-over mechanism is provided for controlling leftward movement of the pin carriage 12 by its spring 25 which, as best seen in FIG. 4, comprises a toothed rack or slide 43 having a slot therein engageable with a pair of studs 44 which are secured to the column indicator bracket 35. The slot in the rack 43 is of such length greater than the distance between the respective outermost surfaces of the studs 44 as to permit movement of the rack 43 relative to the bracket 35 equal to the distance subtended by three denominational orders of the pins 21. An extension of the rack 43 is interconnected With the bracket 35 by a spring 45 which holds the rack in its normal leftmost position of FIG. 4.

Above the toothed portion of the slide 43 and mounted on the keyboard unit for cooperation with that slide is an escapement lever 46 (FIG. 7). The outer end of this lever 46 is secured to the rear end of a shaft 47 which is rotatably mounted in the keyboard unit and extends longitudinally of the machine. The inner end of the lever 46 is provided with a tooth 48 for cooperation with the rack 43, and a spring 49 is connected to the lever 46 in such manner as to exert a downward force upon the inner end thereof.

The forward end of the shaft 47 has a two-armed lever 51 (FIG. 8) rigidly secured thereto in any suitable manner. The outer arm of the lever 51 cooperates at its lower end with a latch lever 52 adjacent the outer end of the latter. This latch lever 52 is mounted on a horizontal pivot 53 at its inner end, and a spring 54 is connected to its outer end to resiliently maintain the same in its normal raised position which is shown in FIG. 8. The lower end of the inner arm of the lever 51 rests upon a shelf portion extending horizontally from the lefthand end of the right-hand escapement pawl 22.

The stem of the three zero control key 42 is provided with a rearwardly extending stud 55 which is shown in dotted lines in FIG. 8 and overlies an intermediate portion of the latch lever 52. Consequently, depression of the three zero control key 42 will swing the latch lever 52 downwardly about its pivot 53 and against the action of its spring 54 to a clearing position below the end of the outer arm of lever 51. Thus unlatching the lever 51 permits the spring49 to swing the escapement lever 46 downwardly to engage its tooth 48 with one of the teeth of the escapement rack 43. Through the agency of the shaft 47, such action of the spring 49 also swings the two-armed lever 51 in a clockwise direction, as seen from the front of the machine in FIG. 8, which depresses the left end of the right-hand escapement pawl 22 to disengage the same from the teeth 19 (FIG. 4) of the pin carriage 12. Such release of the pin carriage, which is not accompanied by downward movement of the lefthand escapement pawl 23 into the path of one of the teeth 19, frees the pin carriage 12 for leftward movement by its spring 25. Such movement, however, is limited by engagement of the leftmost stud 44 with the end of the slot in the escapement rack 43', the latter being restrained against movement by the tooth 48 on the escapement lever 46. These parts are retained in such positions by the spring 49 even though the three zero control key 42 is released and returned to its normal raised position of FIG. 8 by its spring 56. The lower end of the shorter, leftmost arm of the lever 51 overlies the outer portion of the latch lever 52 to prevent return of the latter to its active position by the spring 54.

During the last or resetting portion of the following machine cycle, the return movement of the pin carriage 12 toward its home position of FIG. 4 will cause a stud 57 on the bracket 35 to strike against a finger 58 (FIG. 7) which depends from. the inner end of the escapement lever 46, and, during the final movement of the pin carriage to the right of its normal home position of FIG. 4, to cam the inner end of the esoapement lever 46 upwardly to its normal raised position of FIG. 7. Through the agency of the shaft 47, such movement swings the two-armed lever 51 8 wherein the parts. are latched or retained by the lever 52 which is raised to its active position by the spring 54. This complete disengagement of the escapement lever 46 from. the rack 43 permits the spring 45 to return the latter to its normal position of FIG. 4. It will be appreciated that the rebound of the pin carriage 12 to its home position of FIG. 4 will result in the stud 57 being moved a sufiicientdistance to the left away from the finger 58 to permit subsequent downward movement of the inner end back to its normal position of FIG.

of the lever 46 in response to depression of the three zero control key 42.

The second function previously noted as being performed in response to depression of the three zero control key 42 is accomplished by a slide 59 (FIG. 4) having a special zero stop in the form of a downturned flange 61 (FIG. 2) of sufficient width to span three denominational orders of the stop bars 16 and to cooperate with stops 62 on those bars 16 in the three lowest denominational orders. The slide 59 has a longitudinal slot which slidably embraces a pair of studs 63' (FIG. 4)

that are carried by a transversely extending frame plate 64. A spring 65 is interconnected between the leftmost of these studs 63 and the right end of the slide 59 to urge the latter toward the left of the machine from its normal inoperative position of FIG. 4. The slide 59 also is provided with an upwardly extending finger 66 at its right end for cooperation with a forward extension 67 of the pin carriage 12. A notch in the left-hand forward corner of the slide 59 normally is engaged by a laterally extending finger on a latch slide 68. This slide 68 is provided with a slot (FIG. 2) extending from front to rear of the machine and engaging suitable pins mounted on the frame plate 64. A spring 69 normally maintains the slide 68 in its rearmost active position of FIG. 4. The frame plate 64 is provided with a pair of slots 71 over which the rear end of the latch slide 68 extends. The lower end of a vertically disposed lever 72 extends through the innermost of these slots 71 and the upper portion of the lever 72 cooperates with the three zero control key 42 for movement in response to depression of the latter to swing the lower end of lever 72 forwardly against the latch slide 68. Consequently, depression of the three zero control key 42 moves the latch 68 forwardly to an inoperative position to release the slide 59 for movement to the left from its normal inoperative position of FIG. 4 by the spring 65. Since the pin carriage 12 will be moved three spaces to the left at the same time in response to such depression of the control key 42, the extension 67 will be moved out of the path of the finger 66 and the slide 59 will move its maximum distance, as determined by the length of its slot and the position of the right-hand stud 63. The depending flange -61 thus will be moved into active position with respect to the stops 62 in the three lowest denominational orders. During the following machine cycle, this flange 61 thus will take the place of the zero pins 21 in those orders to permit printing of Zeros but to prevent rearward movement of the rack bars to the nines position.

Return movement of the pin carriage 12 during the latter portion of that machine cycle results in the extension 67 contacting the finger 66 to carry the slide 59 to its normal inoperative position of FIG. 4, wherein it is automatically latched by the slide 68 which is moved rearward by the spring 69.

When it is desired to use the present machine for decimal calculations, it is necessary to functionally eliminate or render inoperative the three lowest, non-decimal denominations. In order to perform this function, some of the above-described novel mechanism is employed, together with additional mechanism, under the control of a whole number key 73. Unlike the three zero control key 42, this whole number control key 73 is latched in active position when depressed, and must be returned to its raised inoperative position manually. Referring specifically to FIGS. 2 and 3, the means for automatically latching the key 73 in depressed position comprises a notch 74 in the key stem and a spring 75 adapted to move the key rearwardly of the machine to engage the notch 74 with an upper key plate 76, as shown in FIG. 2. In order to release the 'key from its latched down, operative position of FIG. 2, it is necessary only to move the upper I end thereof forwardly to disengage the notch 74 from the key plate 76, and the usual key lifting spring 77 will -return the key to its inoperative position of FIG. 3. A forwardly extending, flanged finger on the stem of this whole number key73 engages a rearwardly extending arm of a three-armed lever 78 that is pivotally mounted at 79. The downwardly extending arm of this lever 78 is pivotally'connected to the forward end of a link 81 having a pin and slot connection at its rear end (FIG. 2) with a bell crank pivotally mounted at 82 and comprising a bail 83 having a transversely extending portion at its upper end which is engageable with the tail pieces 84 of the printing hammers in the three lowest denominational orders when moved from its normal, inactive position of FIG. 3 to its active position of FIG. 2 in response to depression of the whole number control key 73. The printing mechanism 14 thus is rendered inoperative in its three lowest denominational orders when the whole number key 73 is in its depressed position.

Depression of the whole number key 73 also moves the latch slide 68 forwardly to release the slide 59in the same manner as results from depression of thethree zero control key 42. This function is accomplished by an inter- 'mediate portion of the three-armed lever 78 which extends through the leftmost slot 71 carriage escapement or step over mechanism is not actuated in response to depression of the whole number key 73, as is the case when the three zero control key 42 is depressed, movement of the slide 59 by its spring 65 to the left from its inactive position of FIG. 4 will be limited by contact of the finger 66 with the extension 67. If the pin carriage 12 is in its home position of FIG. 4 when the whole number key 73 is depressed, which normally will be the case, the resulting movement of slide 59 thus will be limited to the distance of the rebound of the pin carriage 12 which is less than that separating adjacent denominational orders of the pins 21. Consequently, the leftmost row or column of pins 21 will still be operable by any of the digit keys 11. Of course, it is essential that the slide 59 be moved to its maximum leftmost, operative position into blocking relationship with the stop bars 16 in the three lowest denominational orders before the racks 15 are released in a machine cycle. But it is necessary, to effect proper setting of the pins 21, that the pin carriage 12 initially not be stepped over in response to depression of whole number key 73 any farther than as just described. Subsequent depressions of digit keys 11 thus will set their associated pins 21 in the proper leftmost columns. Means are provided for effecting the necessary three order stepover of the pin carriage 12, after all desired digit keys 11 have been actuated, in response to subsequent depression of any one of the regular control keys 26. This means is normally inoperative and is rendered operable by depression of the whole number control key 73 for operation in response to the next depression of a control key 26.

The rear escapement or step-over mechanism previously described, which includes the slide 43, levers 46 and 51 and latch lever 52, is employed in this connection for actuation by the regular control keys 26 if the whole number key 73 has been depressed. Referring to FIG. 3, the forwardly extending arm of the three-armed lever 78 co operates with a beveled stud 85 (shown in dotted lines) which is carried by a lever 86. This lever 86 has a forward end overlying, and in contact with, a ratchet wheel 87, and a rearwardly extending end shown in section in FIG. 8 which, in its normal inactive position as shown therein, is disposed to the right of the horizontal shelf portion comprising the left end of the latch lever 52. This lever 86 is mounted for pivotal and lateral sliding movement on a stub shaft 88 (FIG. 3), and is springurged both downwardly at its front end into engagement with the ratchet wheel 87, and laterally so as normally to maintain its rear end to the right in its inactive position of FIG. 8. Depression of the whole number key 73, however, through the camming action of the forwardly extending arm of lever 78 on the beveled stud 85, swings the rear end of lever 86 to the left to overlie the upper end of the latch lever 52. At this point, of course, the rear escapement or step-over mechanism has not been actuated.

The several control keys 26 are provided with depending tail pieces any of which, upon depression of the associated key, will swing a bail 89 (FIGS. 2 and 8) forwardly. This bail 89 is pivotally mounted on a transverse shaft 91 and has pivotally mounted thereon a pawl 92 that is spring-urged to maintain its forward end in engagement with a ratchet wheel 93. The ratchet wheels 93 and 87 are rigidly secured to a shaft 94 adjacent opposite ends thereof, the shaft 94 being rotatably supported by suitable brackets from a vertical frame plate 95. With this arrangement, the initial portion of downward movement of any of the regular control keys 26 will cause the pawl 92 to impart an increment of rotation to the ratchet wheels 93 and 87. Such movement of the ratchet wheel 87 will raise the forward end of lever 86 (FIG. 3) and depress its rearward end from its position horizontally aligned with, and to the left of, that shown in FIG. 8. This depression of the rear end of lever 86 will trip the latch lever 52 to permit the spring 49 to actuate the rear escapement or step-over mechanism in the manner hereinbefore described. The timing of this operation is such that the pin carriage 12 will be stepped over a distance subtended by three denominational orders immediately in response to the initial portion of a downward movement of any control key 26 and before cam release of the rack return bail 29, whenever the whole number key 73 is in its active, depressed position. And, as will be understood from the preceding description with respect to operation of the three zero key 42, return of the 'pin carriage 12 'at the end of a resulting machine cycle will re-latch the step-over or escapement lever 46 in normal, inactive position. Upon upward return of the depressed control key 26, the members 89 and 92 will be spring-returned to their normal positions of FIG. 2. Since the whole number control key 72 will still be in its active, depressed position, the rear end of the lever 86 will remain in its active position overlying the left end of the latch lever 52. As soon as the whole number key 73 is manually returned to its raised, inoperative position, the rear end of the lever 86 will be spring-returned to its normal position of FIG. 8. Any subsequent depression of one of the control keys 26 will result in depression of the rear end of the lever 86 in the manner above described, but such operation of lever 86 will be ineffective, since its rear end cannot then depress the left end of latch 52.

For visual indication of the particular denominational order or column of pins 21 that is in position for depression by the digit keys 11, the column indicator is pro vided with two pointers 96 that are spaced laterally from each other a distance of three denominational orders to cooperate with the indicia 36 to indicate the pin carriage position when the machine is set for decimal or nondecimal operation, respectively.

From the foregoing. description, it now will be seen how I have accomplished the desired objects and provided a ten-key listing calculator which may be employed optionally for decimal calculations or those involving the use of the British currency system. In effect, the machine normally is conditioned for the latter type of operation in which the three lowest denominational orders are adapted to handle shillings and pence. In this type of operation, it is desirable to be able to enter zeros in those three lowest orders, when an amount being set up in the pin carriage comprises a whole number of pounds, in response to depression of a single key rather than the three successive depressions of the zero digit key otherwise required. This time-saving function is performed in response to depression of the present three zero control key 42. Since use of that control key 42 always will be as the last operation of the'pin carriage and just prior to depression of a regular control key 26, it is essential that the three space step-over of the pin carriage be effected immediately in response to the actuation of the key 42. 1

When the whole number control key 73 is depressed, on the other hand, the required three space step-over of the pin carriage cannot be effected until after the value desired to be entered in the pin carriage has been set therein by depression of the proper digit keys 11. Consequently, although the same step-over mechanism is employed in both types of operations, it is actuated immediately in response to depression of key 42, but not in response to depression of whole number key 73. The latter conditions other normally inoperative mechanism for actuation in response to subsequent depression of a regular control key 26 to effect the desired pin carriage stepover. While the same mechanism also is employed in each type of operation for blocking movement of the actuaton racks, under proper circumstances, to register zeros in the three lowest denominational orders, additional means are provided for preventing any printing in those orders whenever the machine is to be employed in decimal calculations only.

Operation of the three zero control key. 42 has been made as nearly similar physically as possible to that of 9 the regular zero digit key 11, so as to avoid confusing the operator and to effect the desired pin carriage three space step-over before initiation of a machine cycle in response to depression of one of the regular control keys 26. Since a similar three space step-over of the pin carriage is required when using the machine for decimal calculations, it is desirable to use the same step-over mechanism. But the pin carriage step-over should not take place immediately in response to actuation of the whole number control key 73, as above noted, or there could be no setting of pins 21 in the three leftmost columns thereof. If that were allowed to happen, during the subsequent machine cycle the racks 15 in the orders then aligned with those three columns of pins 21 would be released to enter nines, giving an inaccurate result. Consequently, operation of the step-over mechanism is delayed, after depression or the whole number control key 73, until the initial portion of the next following depression of one of the regular control keys 26. And it also will be ap preciated that the manual effort required to depress the added keys 42 and 73 has been minimized by having them operate only against light spring resistance and employing other springs, such as 'for the actual pin carriage step-over and lateral movement of the new zero stop, which are tensioned by operation of the motor.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In a ten-key calculating machine having denominational orders of printing and accumulator mechanisms, means for actuating each said order of mechanisms, a pin carriage having columns of pins for controlling the extent of operation of said actuating means, digit keys openable to selectively actuate said pins and eifect spring movement of said pin carriage the distance between adjacent columns of pins, and motor operated means for enabling spring movement of said actuating means and for returning the operated said actuating means and said pin carriage to normal positions; spring actuated stepover mechanism movable from a home position for effecting movement of said carriage the distance subtended by three columns of said pins, latching means for restraining operation of said step-over mechanism, and manually operable control means for rendering said latching means inoperative.

2. In a calculating machine according to claim 1, motor operated mechanism for returning said step-over mecha nism to said home position.

3. In a calculating machine according to claim 2, a normally inoperative zero stop for controlling operation of said actuating means in the three lowest denominational orders, a spring for moving said zero stop from its normal inoperative position to an operative position, a latch for restraining said zero stop against movement by said spring, and means operable by said manually operable control means for moving said latch to release said zero stop for movement by said spring.

4. In a calculating machine according to claim 3, motor actuated mechanism for returning said zero stop to normal inoperative position.

5. In a calculating machine having pin carriage mechanism, including a carriage with a plurality of denominational orders of selectively settable pins and means constraining said cam'age for movement laterally of the machine from a home position, manually operable digit keys, escapement means controlled by said digit keys for effecting lateral movement of said carriage by said constraining means for the distance between said denominational orders of pins in response to each depression of a said digit key, and operating mechanism, including denominational actuating members corresponding in number to the number of denominational orders of said pins and a manually operable control member for initiating actuation thereof; selectively settable control means, comprising normally inoperative means mounted below said carriage on a stationary part of the machine and operable to block operation of said actuating members in certain lowest ones of said denominational orders regardless of the position of said carriage, and an auxiliary control member manually operable to render operative said normally inoperative means to cause the same to prevent operation of said actuating members in said certain lowest orders in response to actuation of said manually operable control member.

6. In a calculating machine according to claim 5, normal-1y inoperative step-over mechanism rendered operative in response to actuation of said auxiliary control member thereafter to effect lateral movement of said carriage by said constraining means for the distance between the number of denominational orders of said pins equal to said certain lowest orders in response to actuation of said manually operable control member.

7. In a calculating machine according to claim 6, means automatically operable upon actuation of said auxiliary control member to retain the same in actuated position, printing mechanism for all denominational orders normally openable in response to actuation of said manually operable control member, and normally inoperative blocking mechanism rendered operative in response to actuation of said auxiliary control member thereafter to block operation of said printing mechanism in said certain lowest orders upon actuation of said manually operable control member.

8. In a ten key calculating machine having denominational orders of printing and accumulator mechanisms, means for actuating each said order 'of mechanisms, a pin carriage having columns of pins for controlling the extent or operation oi said actuating means, digit keys operable to selectively actuate said pins, spring actuated means controlled by said digit keys, to efiect spring movement of said pin carriage the distance between adjacent columns of pins, motor operated means for enabling spring movement of said actuating means and for returning the operated said actuating means and said pin carriage to normal positions, and regular control keys depressible to elfect operation of said motor operated means; spring actuated step-over mechanism movable from a home position to efiect movement of said carriage the distance subtended by three columns of said pins, latching means for restraining operation of said step-over mechanism, and a plurality of special control keys selectively 0perable to elfect movement of said latching means to permit operation of said step-over mechanism.

9. A calculating machine according to claim 8, wherein one or" said special control keys directly engages said latching means to render the same inoperative.

10. In a calculating machine according to claim 9, normally inoperative latch moving means, and means operable by a second one of said special control keys to render said last recited means operable in response to subsequent depression of a said regular control key.

11. In a calculating machine according to claim 10, manually releasable means for retaining said second special control key in depressed position, and motor operated mechanism for returning said step-over mechanism to said home position, whereby said latching means will restrain operation of said step-over mechanism until a subsequent depression of a said regular control key.

12. In a calculating machine having denominational orders of accumulator mechanism, means for actuating each said order of accumulator mechanism, control means for determining the extent of operation of said actuating means and including a zero stop selectively settable in each order, digit keys operable to selectively actuate said control means and including a zero digit key for actuating said Zero stops; a normally inoperative auxiliary zero stop for controlling operation of said actuating means in the three lowest denominational orders, spring means for moving said auxiliary stop from its normal inoperative position to an operative position, latch means for restraining said auxiliary zero stop against movement, and manually operable means for moving said latch means to release said auxiliary stop for movement by said spring means.

13. A calculating machine according to claim 12 wherein said auxiliary Zero stop is movable by said spring means immediately upon release of said latch means to block return of the latter to operative position.

14. In a calculating machine according to claim 13, motor operated mechanism lfOI' returning said auxiliary zero stop to inoperative position.

15. In a calculating machine having pin carriage mechanism, including a carriage with a plurality of denominational orders of selectively settable pins and means constraining said carriage for movement laterally of the machine from a home position, manually operable digit keys, escapement means controlled by said digit keys for effecting lateral movement ocE said carriage by said constraining means for the distance between said denominational orders of pins in response to each depression of a said digit key, and operating mechanism, including denominational actuating members corresponding in number to the number or denominational orders of said pins; selectively settable control means, comprising normally inoperative means movable from inoperative position to an operative position to block operation or said actuating members in certain lowest ones or said denominational orders, and an auxiliary control member manually operable to effect immediate movement of said normally inoperative means from said inoperative position, motor operated mechanism for returning said pin carriage beyond, and permitting the same to rebound to, said home position, means carried by said carriage for returning said normally inoperative means'to said inoperative position, and means for latching said normally inoperative means in said inoperative position and releasable by said auxiliary control member.

16. In a calculating machine according to claim 15, normally inoperative step-over mechanism rendered operative in response to actuation of said auxiliary control member to effect lateral movement of said carriage by said constraining means for the distance between the number of denominational orders of said pins equal to said certain lowest orders.

17. In a calculating machine according to claim 16, printing mechanism for all denominational orders, and normally inoperative blocking mechanism rendered operative in response to actuation of said auxiliary control member to block operation of said printing mechanism in said certain lowest orders.

References Cited in the file of this patent UNITED STATES PATENTS 1,282,058 Dysart Oct. 22, 1918 1,440,145 Harvey et al. Dec. 26-, 1922 2,062,963 Bennin'ger Dec. 1, 1936 2,279,455 Friden Apr. 14, 1942 2,424,359 Liljestrom July 22, 1947 2,726,037 Landsiedel Dec. 6, 1955 

